As one of devices which emit light by application of a voltage, an organic EL device is known. The organic EL device includes a pair of electrodes and a plurality of organic layers disposed between the electrodes. The organic EL device includes a light emitting layer as one of the organic layers, and emits light by the recombination of a hole and an electron injected by applying a voltage between the electrodes in the light emitting layer.
As a method for forming the organic layer, while there is a plurality of methods such as a vapor deposition method and a coating method, in terms of easiness in steps, the formation of the organic layer by using the coating method is examined. When the organic layer is formed by using the coating method, normally, a solution in which an organic material forming the organic layer is dissolved is firstly coated as a coating liquid to form a coating film, and the coating film is further dried to form the organic layer.
However, the method in which a plurality of organic layers are successively laminated by using the coating method requires the step of coating the coating liquid on an organic layer which is previously formed, and the previously formed organic layer is sometimes eluted into the coating liquid when the coating liquid is coated on the organic layer. As a result, it follows that the film thickness of the previously formed organic layer is reduced, the previously formed organic layer is damaged, or the organic material constituting the previously formed organic layer is mixed into an organic layer to be formed subsequently. Thus, by the method in which the coating liquid is simply coated to successively laminate the plurality of organic layers, it is difficult to manufacture an organic EL device having an intended structure.
In order to solve the above-described problem, there is known a method in which a previously formed organic layer is made insoluble to a coating liquid in advance, and an organic layer is formed on the layer by the coating method. For example, a polymer light emitting material having a crosslinking group such as an oxetanyl group or the like in its molecule is used as a light emitting material, a coating liquid containing the light emitting material is coated to form a coating film, and then a crosslinking reaction is caused to obtain an organic layer which is made insoluble to the coating liquid (see, e.g., JP-T-2004-505169). By using the above-described method, even when the coating liquid is coated on the organic layer, it is possible to prevent the previously formed organic layer from being eluted into the coating liquid and, as the result, it is possible to manufacture an organic EL device having an intended structure.
The above-described light emitting material functioning also as a crosslinking agent needs to have properties required of the crosslinking agent in addition to properties required of the light emitting material. Since the light emitting material functioning also as the crosslinking agent needs to have properties required of both of the crosslinking agent and the light emitting material, the degree of difficulty in the development of the light emitting material functioning also as the crosslinking agent is extremely high when compared with the development of a normal light emitting material without the function as the crosslinking agent. Further, since properties required of an organic material for each of organic layers differ according to the type of the organic layer, it is necessary to individually develop an organic material having properties required of the organic layer and properties required of the crosslinking agent for each of the organic layers, and therefore a load in the development of the material is increased.
To cope with this, there is known a method in which, instead of using one type of an organic material which satisfies the two properties as described above, an organic layer is formed by using a crosslinking agent in addition to an organic material. That is, by using two types of materials including an organic material having properties required of an organic layer and a crosslinking agent having properties required of a crosslinking agent, an insolubilized organic layer can be For example, there is known a method in which, when a light emitting layer is formed, a coating liquid in which a given crosslinking agent is added to a normal light emitting material without the function as the crosslinking agent is used to form an coating film, and the crosslinking agent is further crosslinked to form an insolubilized light emitting layer (see, e.g., JP-A-2006-348274).
Since the crosslinking agent influences properties inherent to an organic material such as the light emitting material or the like, for example, even when the light emitting layer is formed by using the light emitting material having high properties as the light emitting material, by addition of the crosslinking agent, the properties of the light emitting layer are sometimes degraded. In the organic layer formed by using a conventional given crosslinking agent, the influence exerted on the properties of the organic material by the crosslinking agent is significant so that the properties thereof is sharply degraded by the addition of the crosslinking agent. Consequently, an organic EL device having such organic layer does not necessarily have sufficient luminous efficiency. Although the amount of addition of the crosslinking agent can be reduced in order to suppress the influence caused by the addition of the crosslinking agent, the insolubilization of the organic layer becomes insufficient in this case, and it becomes difficult to manufacture the organic EL device having the intended structure, as described above.
Accordingly, an object of the present invention is to provide an organic electroluminescent device and a manufacturing method thereof which allow suppression of a reduction in luminous efficiency resulting from addition of a crosslinking agent, and easy manufacture of a device having an intended structure.
The present invention relates to an organic electroluminescent device comprising a pair of electrodes, and a plurality of organic layers disposed between the electrodes and including an organic light emitting layer, wherein one of the organic layers contains an organic material forming the organic layers and a polymer obtained by polymerizing a polymerizable compound capable of exhibiting charge transportability.
The present invention relates to the organic electroluminescent device, wherein the polymerizable compound is an aromatic compound.
The present invention relates to the organic electroluminescent device, wherein the aromatic compound is a fluorene compound.
The present invention relates to the organic electroluminescent device, wherein the ratio of amount of the polymer obtained by polymerizing the polymerizable compound relative to the total weight of the organic layers is not less than 5% by weight and less than 40% by weight.
The present invention relates to the organic electroluminescent device, wherein the polymerizable compound has at least one group selected from the group consisting of a vinyl group, an ethynyl group, a butenyl group, an acryloyl group, an acryloylamino group, a methacryloyl group, a methacryloylamino group, a vinyloxy group, a vinylamino group, a silanol group, a cyclopropyl group, a cyclobutyl group, an epoxy group, an oxetanyl group, a diketenyl group, an epithio group, a lactonyl group, and a lactamnyl group.
The present invention relates to the organic electroluminescent device, wherein the polymerizable compound is phenyl fluorene acrylate.
The present invention relates to a method for manufacturing an organic electroluminescent device comprising a pair of electrodes and a plurality of organic layers disposed between the electrodes,the method comprising a step of preparing a substrate on which one of the pair of electrode has been formed, an organic layer formation step of forming the plurality of organic layers by using a coating method, and an electrode formation step of forming the other electrode of the pair of electrodes, wherein, in the organic layer formation step, a coating film is formed by the coating method in which is used a coating liquid containing an organic material forming the organic layers and a polymerizable compound capable of exhibiting charge portability, and the organic layers are formed by polymerizing the polymerizable compound.
The present invention relates to the method for manufacturing an organic electroluminescent device, wherein the polymerizable compound is phenyl fluorene acrylate.
The present invention relates to the method for manufacturing an organic electroluminescent device, wherein the weight ratio of the organic material to the polymerizable compound in the coating liquid is from 95:5 to 60:40.
The present invention relates to a planar unit comprising the organic electroluminescent device.
The present invention relates to a lighting unit comprising the organic electroluminescent device.
The present invention relates to a display unit comprising the organic electroluminescent device.